The world is infected by a virus and you have learned about a lab that has the cure. The mastermind behind the creation of the antidote has fallen victim to insanity. Even before going mad, the chemist was a paranoid individual. He protected the formula in his lab behind a safe wall of codes and puzzles. He has disappeared and left his antidote in his lab.
If you and your fellow survivors can work quickly, you can acquire the antidote before the virus kills you and the rest of the world.